REPORTING WiFi CHANNEL MEASUREMENTS TO A CELLULAR RADIO NETWORK

ABSTRACT

A method and devices for providing measurements of WiFi network channels to a cellular radio network are disclosed. According to one aspect, the invention provides a method that includes preparing, at a node of the cellular radio network, a request for measurement of at least one WiFi channel. The measurement is to be provided by at least one user equipment having a WiFi transceiver and a cellular radio transceiver. The method includes transmitting, from the node of the cellular radio network, the request to the at least one user equipment. The node of the cellular radio network receives, from the at least one user equipment, at least one measurement of the at least one WiFi channel.

TECHNICAL FIELD

The present invention relates to a method and devices for providing WiFichannel measurement reports to a cellular radio network.

BACKGROUND

WiFi, also termed WLAN, has become a ubiquitous wireless technology fordata communication in the unlicensed radio spectrum. The Institute ofElectrical and Electronic Engineers, IEEE, standard IEEE 802.11 definesthe protocol stack and functions used by WiFi access points, APs. In thelicensed radio spectrum 3^(rd) generation partnership project, long termevolution, 3GPP LTE, wireless communication technology is rapidly beingdeployed. LTE is the 4^(th) generation of wireless cellularcommunications. The protocol stack of LTE is currently defined by the3GPP. The rapid increase in cellular data usage has prompted wirelessoperators to turn to using WiFi as a means to offload traffic from thecongested licensed radio spectrum.

WiFi and cellular radio networks have traditionally by implemented andoperated separately from one another. For example, FIG. 1 shows a knowncellular radio network 10 and a known WiFi network 20. Each of networks10 and 20 are independent of the other, even though coverage provided byeach network 10 and 20 may overlap in some areas. The cellular radionetwork includes a plurality of base stations 12 that contain radiosthat communicate over a defined geographic area called a cell. The basestations 12 may be, for example, evolved Node B, eNB, base stations ofan evolved Universal Terrestrial Radio Access Network, eUTRAN, or LTEnetwork. The air interface of the base stations 12 may be orthogonalfrequency division multiple access, OFDMA, on the downlink, and singlecarrier frequency division multiple access, SC-OFDMA, on the uplink.

Each base station 12 may be in communication with a serving gateway S-GW14 using an S1 protocol. The S-GW 14 is a communication interfacebetween the base stations 12 and the Internet and/or a backhaul network.As such S-GW 14 routes and forwards user data packets, while also actingas the mobility anchor for the user plane during inter-eNB handovers andas the anchor for mobility between LTE and other 3GPP technologies.

The base stations 12 are also in communication with a mobile managemententity, MME, 16. The MME 16 is a control node for an LTE access-network.The MME 16 is responsible for idle mode UE 24, User Equipment, trackingand paging procedures including retransmissions. The MME 16 is involvedin the bearer activation/deactivation process and is also responsiblefor choosing the S-GW 14 for a UE 24 at the UE's initial entry into theLTE network and at a time of intra-LTE handover.

The MME 16 is responsible for authenticating the user, for generationand allocation of temporary identities to UEs, for authorization of theUE 24 to camp on the service provider's Public Land Mobile Network(PLMN) and enforces UE roaming restrictions. The MME is the terminationpoint in the network for ciphering/integrity protection for non-accessstratum, NAS, signaling and handles security key management. Lawfulinterception of signaling is also supported by the MME 16. Further, theMME 16 also provides the control plane function for mobility between LTEand second generation/third generation, 2G/3G, access networks.

The WiFi network 20 includes wireless access points 22. Each WiFi accesspoint functions as a communication interface between a user equipment24, such as a computer, and the Internet. The coverage of one or more(interconnected) access points—called hotspots—can extend from an areaas small as a few rooms to as large as many square miles. Coverage inthe larger area may require a group of access points with overlappingcoverage.

Cellular radio networks, such as the communication network 10, and theWiFi network 20 utilize two independent radio air interfaces andnetworks, each with their own operations, administration and management,OAM, infrastructure. Since the two network architectures are separated,the ability to perform fast and reliable mobility (handoff) ofsubscriber data sessions between the two networks is severely limited.For example, seamless roaming from LTE to WiFi and back without loss ofdata packets is a hugely complex task with today's separate networks.

The vast majority of smartphone devices now manufactured include both3GPP cellular (3G and 4G) and WiFi capabilities. These user equipment 24have separate radio and protocol stacks for each technology (termed dualstack or dual radio). Both wireless technologies operate simultaneouslyand independently. There is no method for the cellular radio network toknow the radio status of the WiFi link. As such, the cellular radionetwork cannot make any admission, mobility or load balancing decisionswith respect to use of the WiFi link.

SUMMARY

The present invention advantageously provides a method and devices forproviding measurements of WiFi network channels to a cellular radionetwork. According to one aspect, the invention provides a method thatincludes preparing, at a node of the cellular radio network, a requestfor measurement of at least one WiFi channel. The measurement is to beprovided by at least one user equipment having a WiFi transceiver and acellular radio transceiver. The method includes transmitting, from thenode of the cellular radio network, the request to the at least one userequipment. The node of the cellular radio network receives, from the atleast one user equipment, at least one measurement of the at least oneWiFi channel.

According to this aspect, in some embodiments, the measurement is areceived signal strength indication, RSSI. In some embodiments, themeasurement is a received channel power indication, RCPI, and the methodfurther includes converting the RCPI into units of at least one of dBmand mW. In some embodiments, the node of the cellular radio network is along term evolution, LTE, base station. In some embodiments, the methodmay further include performing, at the node of the cellular radionetwork, a power saving function based on the at least one measurement,the power saving function including instructing a user equipmentcellular radio transceiver to enter a sleep mode. In some embodiments,the method includes performing, at the node of the cellular radionetwork, a WiFi network mapping function based on the at least onemeasurements. The network mapping function may include creating a listof WiFi channels accessible by at least one user equipments. The methodmay further comprise performing, at the node of the cellular radionetwork, a user equipment handoff function based on the at least onemeasurement. The user equipment handoff function may includediscontinuing allocation of a cellular radio network channel to a userequipment. In some embodiments, the method includes comparing, at thenode of the cellular radio network, at least one measurement to at leastone threshold to determine when a WiFi channel quality is greater than acellular radio channel quality.

According to another aspect, the invention provides a cellular radionetwork node configured to process signals compatible with a cellularradio network protocol. The cellular radio network node includes amemory, a cellular radio transceiver and a processor. The memory isconfigured to store an identification of at least one user equipment.The memory is further configured to store at least one measurement of aWiFi channel received from at least one of the at least one userequipment. The cellular radio receiver is configured to send the requestfor measurement of at least one WiFi channel to the at least oneidentified user equipment. The cellular radio receiver is furtherconfigured to receive from the at least one identified user equipment atleast one WiFi channel measurement. The processor is in communicationwith the memory and the cellular radio transceiver and is configured togenerate the request for measurement. The processor is furtherconfigured to cause the cellular radio transceiver to send the requestfor measurement of at least one WiFi channel to the at least oneidentified user equipment. The processor is further configured to causethe memory to store the at least one measurement of the WiFi channelreceived from the at least one of the at least one user equipment.

According to this aspect, in some embodiments, the processor is furtherconfigured to perform a power saving function based on the at least oneWiFi channel measurement. The power saving function may include causingthe cellular radio transceiver to send an instruction to a userequipment cellular radio transceiver to enter a sleep mode. Theprocessor may further be configured to perform a WiFi network mappingfunction. The network mapping function may include creating a list ofWiFi channels accessible by at least one user equipments. In someembodiments, the processor is further configured to perform a userequipment handoff function. In some embodiments, the request formeasurement specifies at least one WiFi channel to be measured. Thespecified at least one WiFi channel is selected from a list of WiFichannels reported by a user equipment. In some embodiments, theprocessor is embedded in a radio resource controller of a long termevolution, LTE, base station.

According to yet another aspect, the invention provides a user equipmenthaving a cellular radio unit to receive a request from a cellular radiobase station requesting the user equipment to measure at least one WiFichannel, and to transmit to the cellular radio base station a reporthaving the measurement of the at least one WiFi channel. The userequipment also includes a WiFi transceiver configured to receive signalsfrom a WiFi access point, and to process the received signals todetermine a measurement of at least one WiFi channel. The user equipmentalso includes an interface to facilitate communications between thecellular radio unit and the WiFi transceiver.

According to this aspect, in one embodiment, the report having themeasurement is generated in the WiFi transceiver, and in anotherembodiment the report having the measurement is generated in thecellular radio unit. In some embodiments, the report having themeasurement includes a list of at least one WiFi channel received by theuser equipment, each one of the at least one WiFi channel associatedwith a different measurement. In some embodiments, the request includesa list of WiFi channels to be measured.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a block diagram of known cellular radio network and a knownWiFi network;

FIG. 2 is a block diagram of a communication system having a cellularradio network node, a WiFi access point, and a user equipmentconstructed in accordance with principles of the present invention;

FIG. 3 is a block diagram of a cellular radio network node constructedin accordance with principles of the present invention;

FIG. 4 is a flowchart of an exemplary process for acquisition of WiFichannel measurements by a cellular radio network node; and

FIG. 5 is a flowchart of an exemplary process for acquiring andtransmitting a channel measurement at a user equipment in response to arequest from a cellular radio network node.

DETAILED DESCRIPTION

Before describing in detail exemplary embodiments that are in accordancewith the present invention, it is noted that the embodiments resideprimarily in combinations of apparatus components and processing stepsrelated to providing WiFi channel measurement reports to a cellularradio network. Accordingly, the system and method components have beenrepresented where appropriate by conventional symbols in the drawings,showing only those specific details that are pertinent to understandingthe embodiments of the present invention so as not to obscure thedisclosure with details that will be readily apparent to those ofordinary skill in the art having the benefit of the description herein.Of note, although the description herein references cellular radio andWiFi, the invention is not limited to such. It is contemplated thatcommunications based unlicensed or licensed communication technologiescan be used for one or both of the cellular radio and WiFi technologiesdescribed herein.

As used herein, relational terms, such as “first” and “second,” “top”and “bottom,” and the like, may be used solely to distinguish one entityor element from another entity or element without necessarily requiringor implying any physical or logical relationship or order between suchentities or elements.

Since one of the motivations of supplementing cellular radio networkcapacity with WiFi is to autonomously offload data traffic, the networknodes that must make the decision to move end user sessions from onenetwork to another currently should have means of determining theability of the other network node to receive the offloaded traffic. Inparticular, to ascertain whether to handoff LTE traffic to the WiFinetwork, the LTE eNB should have information about the channel qualityof links between one or more WiFi access points and user equipment.

Returning now to the drawing figures, there is shown in FIG. 2 a blockdiagram of a communication system 26 having a cellular radio networknode 28, a WiFi access point 30, and a user equipment 32 constructed inaccordance with principles of the present invention. The cellular radionetwork node can be, for example, a 3GPP node, such as a long termevolution, LTE, base station. The cellular radio network node 28includes a radio resource controller 34 that handles control planesignaling between the user equipment 32 and the cellular radio network.Functions of the radio resource controller 34 may include establishingand releasing a connection between the UE 32 and another entity, such asanother user equipment in the network or another caller from a landline. The functions of the radio resource controller 34 may also includebroadcasting system information, mobility functions such as admissionand handoff, paging notification, UE authentication, OAM functions, andpower control.

In particular, the radio resource controller 34 may function to preparea request for measurement of at least one WiFi channel, transmit therequest to at least one user equipment 32 and receive from the at leastone user equipment 32 at least one measurement of the at least one WiFichannel. Further, the cellular radio resource controller 34 may performfunctions of mapping a WiFi network. Such mapping may includedetermining an identification of WiFi access points within and without acell associated with the cellular radio network node, and channelsassociated with each identified WiFi access point.

The user equipment, UE, 32 includes a cellular radio transceiver 36 tocommunicate wirelessly with the cellular radio network node 28, a WiFitransceiver 38 to communicate with the WiFi access point 30, and aninterface 40 to facilitate communication between the cellular radiotransceiver 36 and the WiFi transceiver 38. The WiFi transceiver 38includes a WiFi channel measurement unit 42 to generate WiFi channelmeasurements.

In operation, the cellular radio resource controller 34 of the cellularradio network node 28 prepares a request for measurement of at least oneWiFi channel. The preparation of the request may be performedperiodically, or in response to a determination that traffic is to beoffloaded to the WiFi network, or in the event of admission of a userequipment to the cellular radio network, or in the event of facilitatinga handoff of a user equipment 32 from the cellular radio network to theWiFi network. The request may include a list of WiFi channels, i.e.,frequencies, for which the channel measurements are to be taken. Forexample, the list of channels may be selected from a list of WiFichannels reported by a UE. Alternatively, or in addition, the requestmay include a list of one or more UEs 32 whose WiFi links are to bemeasured. Alternatively, or in addition, the request may specify a listof one or more WiFi access points whose downlink channels to one or moreUEs are to be measured. The request may further include an instructionto one or more UEs 32 to perform a channel measurement for one or moreof the channels of the WiFi network.

The request prepared by the cellular radio resource controller 34 issent by the cellular radio network node 28 to one or more UEs 32. Thecellular radio transceiver 36 receives the request and demodulates anddecodes the request. The WiFi transceiver 38, if not already activated,is now activated. The request is sent to the WiFi transceiver 38 via theinterface 40. The WiFi transceiver 38 receives and processes therequest. For instance, the WiFi transceiver 38 may identify a WiFichannel specified by the request and retrieve a previously determinedchannel quality indicator for the specified channel. Alternatively, theWiFi transceiver 38 may initiate a transmission on the uplink of thechannel to one or more WiFi access point 30 and receive one or moreresponsive downlink signals on the specified channels from the one ormore WiFi access points 30. The WiFi channel measurement unit 42 maythen perform a measurement of channel quality based on each receiveddownlink signal. A channel measurement may be performed for each of aplurality of channels. The channel measurement may be one of a channelquality indicator, CQI, a received signal strength indication, RSSI, areceived channel power indicator, RCPI, or other channel measurement.The RCPI may be converted to dBm or mW. This conversion may be performedin the cellular radio network node or in the user equipment.

The channel measurements are sent via the interface 40 from the WiFitransceiver 38 to the cellular radio transceiver 36. In someembodiments, the channel measurements may be assembled into a report byone of the WiFi receiver 38 and the cellular radio transceiver 36. Thecellular radio transceiver 36 sends a channel measurement report to thecellular radio resource controller 34. The cellular radio resourcecontroller 34 may use the channel measurement report for one or morepurposes. For example, the channel measurement report may be used todetermine which one or more of a plurality of UEs is to be handed off toone or another WiFi access point. If the cellular radio resourcecontroller 34 determines that a UE 32 is to be handed off, the cellularradio resource controller 34 may terminate a cellular radio connectionto the UE 32 to be handed off. A condition for determining if a UE 32 isto be handed off to the WiFi network may be a threshold to which thechannel measurement is compared. For example, if a first channelmeasurement of a first channel exceeds a threshold, a decision may bemade to handoff a UE 32 corresponding to the first channel to the WiFiaccess point to which the channel corresponds.

FIG. 3 is a more detailed block diagram of the cellular radio networknode 28 of FIG. 2. The cellular radio network node 28 includes thecellular radio resource controller 34 and a cellular radio transceiver44. The radio resource controller 34 includes a memory 46 and aprocessor 48. The memory 46 stores a UE list 50 and WiFi channelmeasurements 52. In some embodiments, the memory 46 may store additionaldata, such as identities of a plurality of WiFi access points and thechannels associated with each WiFi access point. The memory may alsostore locations of the WiFi access points and/or an indication whether aWiFi access point is within or without a cell associated with thecellular radio network node 28.

The processor 48 performs functions related to control of radioresources of the cellular radio network node 28. For example, theprocessor 48 includes a request generator 54 that generates requests forWiFi channel measurements. The requests may specify one or more WiFichannels to be measured. The WiFi channels may be associated with one ormore UEs and/or one or more WiFi access points.

The processor 48 may also initiate power saving functions 56. Forexample, the power saving functions 56 may include instructions to powerdown the cellular radio transceiver 36 and/or the WiFi transceiver 38. Apower down instruction to power down a UE's WiFi transceiver 42 may begenerated in response to a determination that a WiFi channel used by theUE 32 is of poor quality. As another example, a power down instructionto power down a UE's cellular radio transceiver may be generated inresponse to a determination that a WiFi channel used by the UE 32 isstrong. Thus, the power saving functions 56 may instruct one or both ofthe cellular radio transceiver 36 and the WiFi transceiver 38 to enter asleep mode.

The processor 48 may also initiate WiFi network mapping functions 58.Such mapping may include 1) determining an identification of WiFi accesspoints within and without a cell associated with the cellular radionetwork node, 2) determining channels associated with each identifiedWiFi access point, 3) determining UEs in communication with each WiFiaccess point, 4) generating a list of WiFi channels accessible by one ormore UEs, and/or 4) determining a channel quality for each WiFi channelassociated with each UE and each WiFi access point.

The processor 48 may also initiate handoff functions 60. Such handofffunctions may include 1) determining that quality of a cellular radiochannel to which a UE is assigned has dropped below a threshold, and/or2) determining that quality of a WiFi channel to which a UE is assignedis above a threshold, and 3) terminating the UE's use of the cellularradio channel. Additional coordination between the WiFi network and thecellular radio network to complete a handoff is beyond the scope of thisdisclosure.

The cellular radio transceiver 44 of the cellular radio network node 28sends a request for measurement of at least one WiFi channel to at leastone UE 32, and receives from the at least one UE 32 at least one WiFichannel measurement.

FIG. 4 is a flowchart of an exemplary process for acquisition of WiFichannel measurements by a cellular radio network node 28. The processincludes preparing, at the cellular radio network node 28, a request formeasurement of a WiFi channel (block S100). The request for measurementof the WiFi channel is transmitted from the cellular radio network node28 (block S102). A measurement of the WiFi channel is received at thecellular radio network node 28 from a UE 32 that received the request(block S104). At least one of a power saving function, a WiFi networkmapping function and a handoff function, as described above, isinitiated at the cellular radio network node 28 based on a measurementof a WiFi channel (block S106).

An exemplary process for acquiring and transmitting a channelmeasurement at a user equipment in response to a request from a cellularradio network node is described with reference to FIG. 5. A request fora measurement of a WiFi channel is received by a cellular radiotransceiver 36 of a UE 32 from a cellular radio network node 28 (blockS108). A WiFi transceiver of the user equipment is activated if notalready activated (block S110). Signals from a WiFi access point 30 arereceived at a WiFi transceiver 38 of the UE 32 (block S112). The signalsare processed to determine a measurement of the channel (block S114).The measurement is reported to the cellular radio network node 28 viathe cellular radio transceiver 36 of the UE 32 (block S116).

The present invention can be realized in hardware, or a combination ofhardware and software. Any kind of computing system, or other apparatusadapted for carrying out the methods described herein, is suited toperform the functions described herein. A typical combination ofhardware and software could be a specialized computer system, having oneor more processing elements and a computer program stored on a storagemedium that, when loaded and executed, controls the computer system suchthat it carries out the methods described herein. The present inventioncan also be embedded in a computer program product, which comprises allthe features enabling the implementation of the methods describedherein, and which, when loaded in a computing system is able to carryout these methods. Storage medium refers to any volatile or non-volatilestorage device.

Computer program or application in the present context means anyexpression, in any language, code or notation, of a set of instructionsintended to cause a system having an information processing capabilityto perform a particular function either directly or after either or bothof the following a) conversion to another language, code or notation; b)reproduction in a different material form.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A method of providing measurements of one or morechannels of a WiFi network to a cellular radio network, the methodcomprising: preparing, at a node of the cellular radio network, arequest for measurement of at least one WiFi channel, the measurement tobe provided by at least one user equipment having a WiFi transceiver anda cellular radio transceiver; transmitting, from the node of thecellular radio network, the request to the at least one user equipment;and receiving, at the node of the cellular radio network, from the atleast one user equipment, at least one measurement of the at least oneWiFi channel.
 2. The method of claim 1, wherein the measurement is areceived signal strength indication, RSSI.
 3. The method of claim 1,wherein the measurement is a received channel power indication, RCPI,the method further comprising converting the RCPI into units of at leastone of dBm and mW.
 4. The method of claim 1, wherein the node of thecellular radio network is a long term evolution, LTE, base station. 5.The method of claim 1, further comprising performing, at the node of thecellular radio network, a power saving function based on the at leastone measurement, the power saving function includes instructing a userequipment cellular radio transceiver to enter a sleep mode.
 6. Themethod of claim 1, further comprising performing, at the node of thecellular radio network, a WiFi network mapping function based on the atleast one measurements, the network mapping function include creating alist of WiFi channels accessible by at least one user equipments.
 7. Themethod of claim 1, further comprising performing, at the node of thecellular radio network, a user equipment handoff function based on theat least one measurements.
 8. The method of claim 7, wherein the userequipment handoff function includes discontinuing allocation of acellular radio network channel to a user equipment.
 9. The method ofclaim 1, further comprising comparing, at the node of the cellular radionetwork, the at least one measurement to at least one threshold todetermine when a WiFi channel quality is greater than a cellular radiochannel quality.
 10. A cellular radio network node configured to processsignals compatible with a cellular radio network protocol, the cellularradio network node comprising: a memory configured to store: anidentification of at least one user equipment; and at least onemeasurement of a WiFi channel received from at least one of the at leastone user equipment; a cellular radio transceiver configured to: send therequest for measurement of at least one WiFi channel to the at least oneidentified user equipment; and receive from the at least one identifieduser equipment at least one WiFi channel measurement; and a processor incommunication with the memory and the cellular radio transceiver, theprocessor configured to; generate the request for measurement; cause thecellular radio transceiver to send the request for measurement of atleast one WiFi channel to the at least one identified user equipment;and cause the memory to store the at least one measurement of the WiFichannel received from the at least one of the at least one userequipment.
 11. The cellular radio network node of claim 10, wherein theprocessor is further configured to perform a power saving function basedon the at least one WiFi channel measurement, the power saving functionincludes causing the cellular radio transceiver to send an instructionto a user equipment cellular radio transceiver to enter a sleep mode.12. The cellular radio network node of claim 10, wherein the processoris further configured to perform a WiFi network mapping function, thenetwork mapping function including creating a list of WiFi channelsaccessible by at least one user equipments.
 13. The cellular radionetwork node of claim 10, wherein the processor is further configured toperform a user equipment handoff function.
 14. The cellular radionetwork node of claim 10, wherein the request for measurement specifiesat least one WiFi channel to be measured.
 15. The cellular radio networknode of claim 14, wherein the specified at least one WiFi channel isselected from a list of WiFi channels reported by a user equipment. 16.The cellular radio network node of claim 10, wherein the processor isembedded in a radio resource controller of a long term evolution, LTE,base station.
 17. A user equipment, comprising: a cellular radio unitconfigured to: receive a request from a cellular radio base stationrequesting the user equipment to measure at least one WiFi channel; andtransmit to the cellular radio base station a report having themeasurement of the at least one WiFi channel; and a WiFi transceiverconfigured to; receive signals from a WiFi access point; and process thereceived signals to determine a measurement of at least one WiFichannel; and an interface to facilitate communications between thecellular radio unit and the WiFi transceiver.
 18. The user equipment ofclaim 17, wherein the report having the measurement is generated in theWiFi transceiver.
 19. The user equipment of claim 17, wherein the reporthaving the measurement is generated in the cellular radio unit.
 20. Theuser equipment of claim 17, wherein the report having the measurementincludes a list of at least one WiFi channel received by the userequipment, each one of the at least one WiFi channel associated with adifferent measurement.
 21. The user equipment of claim 17, wherein therequest includes a list of WiFi channels to be measured.